One of those is a SMT diode (it's marked D1), probably ultrafast or schottky given the nature of the device. U1 is almost certainly a standard 5V buck converter IC (probably with UVLO), of which many many exist and all pretty much do the same thing: provide a regulated DC output from a DC input.

I don't think it does anything fancy like MPPT (and therefore I dispute the claim that "SunVolt performs very efficiently") because with a fixed 5V output that you'd need to ensure compatibility with devices, you don't have the option of doing any kind of current control.

In an instance where you're using just a PV panel to charge one unmodified phone or laptop, then you can't. As I mentioned, with a fixed 5V output (or whatever voltage your laptop uses), you don't have the option of doing any kind of current control, therefore MPPT is not possible.

But if you were to attach a battery pack to the PV cell to buffer the energy, then you would be able to use MPPT. Alternatively if somehow you were able to access your phone/laptop's charge controller to allow variable charge current, then MPPT could be implemented.

Many smartphones for example can select between two or three charge rates depending on whether they're connected to a USB 2.0 port, wall wart, or something proprietary, one way of "hacking it" would be to have the PV panel toggle the smartphone between these three charge rates, to achieve some approximation of MPPT.

If you're interested in MPPT, then probably attaching a battery pack to the PV cell would be the wisest choice.

Sounds cool but with all technical achievements aside, iPhones (or any rechargeable) don't like to be interrupted while charging. Of course you can. I'm saying long term battery wise. Every time a cloud goes over it would stop and start. I agree above. Thats what batteries are for. Maybe for an emergency I guess.